Independent insertion devices controlled off-line from image forming apparatuses and capable of inserting into respective envelopes a large amount of enclosures on which images are formed by the image forming apparatuses (hereinafter “enclosures”) are known.
However, in such insertion systems in which the insertion device is controlled off-line from the image forming apparatus, time efficiency is low, in particular in small-lot insertion processing, because image formation on enclosures and insertion of the enclosures into envelopes are performed by separate devices. Therefore, connecting the image forming apparatus to the insertion device is preferred to enable online insertion, thereby reducing loss in time.
Additionally, there are insertion systems that include a folding device to fold enclosures to be inserted into envelopes. However, known inline insertion systems do not offer inserting a sheet folded in single-sheet folding together with sheets folded in batch folding in an identical envelope together at a time. It is to be noted that the terms “single-sheet folding” and “batch folding” used in this specification mean folding a single sheet at a time and folding multiple sheets stacked one on another at a time, respectively. Specifically, in conventional insertion systems, multiple sheets inserted into a single envelope are regarded as “a set” and generally subject to identical folding method.
For example, JP-2003-002527-A proposes an insertion system that includes multiple feeding units to feed first and second enclosures, a first transport unit to transport the first enclosure through a first route individually and sequentially, and a second transport unit to transport a set of second enclosures through a second route. The second transport unit stacks the set of second enclosures on the first enclosure.
Although this insertion system can offer a variety of folding and insertion processing, to insert the sheet folded in single-sheet folding and sheets folded in batch folding into an identical envelope, it is necessary to set those sheets manually in the first and second transport units, respectively, after those sheets are folded. That is, in this insertion system, single-sheet folding and batch folding cannot be designated at a time.